Signaling system



Dec. 26, 1944. v F. s. GREENE 2,365,949

SIGNALING SYSTEM Original Filed July 13, 1942 6 Sheets-Sheet l INVENTOR Frank S. G re-ene ATTORNEYS Deco 26, 1944. F, s, GREENE SIGNALING SYSTEM Original Filed July l5. 1942 6 Sheets-Sheet 2 V mm. mm. MN QN s d, um. um. UN N .S

R 0 T N E V W Frank S. Greene WA/ 4 h? ATTORNEYS Dea, 26, 1944.

F. s. GREENE SIGNALING SYSTEM 6 Sheets-Sheet 5 Original Filed July l5, 1942 him Dec. 26, i944, F, s, GREENE SIGNALING SYSTEM Original Filed July l5, 1942 6 SheecsSheet 4 INVENTOR .Frank S. Greene /05 mug f-7c7 ATTORN EYS Dec, 25, i944. F- s GREENE 2,365,949

SIGNALING SYSTEM Original Filed July 13, 1942 6 Sheets-Sheet 5 INVENTOR Frank S. Greene `ATTORNEYS Original Filed July 13, 1942 6 Sheets-Sheet 6 mw NM INVENTOR Frank S. Greene rye@ ATTORNEYS Patented Dec. 26, 1944 zessen SIGNALING SYSTEM Frank S. Greene, Cleveland', Ohio, assignor to William M. ONeil, ClevelandHeights," Ohio original application July 13, v,1942, serial No.' 450,693. Dividedand thisapplication October 12. 1943, Serial No. 505,937

, 26 Claims.

This invention relates to a method of and apparatus for indicating the location and` course oitravel of air or water craft, the present application being a continuation in part of application, Serial No. 450,693, filed July 13, 1942.

, It is the purpose of the present invention to -provide means by which the -pilot of a craft travleling within a predetermined geographical area -may be informed at all times of the location of the craft and the course over which the craft has traveled.

. More specifically, the present invention contemplates the provision of intersecting directional radio beams of different frequencies which are so arranged as to form a checkerwork` of f intersecting beams over the area within which the craft travels and the use of positiontand course indicating devices on the craft which are automatically controlled by a series of radio receiving vcircuits tuned to the frequencies` of the radio beams.

"With the above and other objects in view the invention may be said to comprise the method and apparatus as illustrated in the accompanying drawings hereinafter described and particu--v -larly set forth in the appended claims, together with such variationsA and modicatons thereof as will be apparent to thoseskilled in the art to f which the invention pertains.

Reference should be had .to the accompanying- `cate` two series of radio beams of different fref quencies and in which the areas enclosed `by heavy lines indicate subdivisions, each of-which enclosesa group of beam, intersections which l includes all of theopossible frequency combinations;

Fig. 2vis a` general diagram of the indicating `apparatus on the air or water-craft which` is conf. `ftrollecl by the -radio beams;

Fig. 3l isa. `wiring diagram showing vthe control `'panel circuits `and switches;

f Fig. 4fis a detail viewof one ofthe enea-way `trip switches;

1 Fig, 5 isa fragmentary view` showing onev of thestylus operating circuits;

."Fig. Gris a diagrammatic viewfshowing almodified'form of radio control;

V Eig. 7 :isi aplan view of the` graphic position indicator; Y

Eigr-S isa -section taken on the lineindicated at 8-8 in Fig. '7;`

. Fig.. 9is` a detail. view showing one of the ratchets and its solenoid actuator;

. malais a detaiLview showing one of the swiv- -.eled pointer guides;

- Fig. 11,is.a wiringdiagram showing the actuating circuits` for the. solenoids of the graphic indicator;

Fig. l2 is a wiring diagram showing modified lamp control circuits;

Figa-Bis a. wiring diagram showing means for automatically, compensating for failure of one or more .ofthe radio receiving circuits;

Yofi thecontrol panels.

. Figure 1 of-the drawings shows a checkerwork ,ofintersectingdirectional radio beams trans- Umittedfrom a series of stations A which may be distributed. along anedge `of the checkerwork area. `Assuming thatthe stations extend in a general northand south. direction, theV checkerworkmaybe. formed by aseriesof beams extend- .,ingnortheast anda second series of beams exv` tendingsoutheast. .The beams of each series are preferablyparallel and uniformly spaced and the 4.stationswi may Yeachmtransmit two diverging beams or.a single beam, whichever will permit 4oitl'iemost convenient arrangement of the stationsA. Each series of parallel-beams will utilize a rpredetermined,number of beam frequencies i which recur in regular order.

As shown, the

.northeast .beams-havefour frequencies which are .indicated by thenumerals l, 2, 3 and 4, and the southeast` beams Ahave four frequencies which across `thecheckerwork,and the same is true of f frequencies a; b, c and d. The lines indicating the beams Aofl frequencies I, 4, a, and d form the borderlines .of subdivisions4 B, each of which includes .a group. of ,sixteen beam intersections which` include eachpf the possible combinations hof,.frequencies inthe intersectingbeams which .,areindicated. in the'subdivision B1 as la, Ib, lc

`and. lo, andthe same. combination of the numer- ,.als,|. 2,. 3` and 4 with the letters a, b, c, and du The borders of the subdivisions B are indicated byheavy lines and these subdivisions are spaced apartlcy` gaps C whichextend northeast and gaps D which extend southeast.

,The Checkerwork ofradio `beams serve to ener- 1,xgizezradio `receivingcircuits on, the air or water Graftthat aratuned to the frequencies ofthe radiobeamsand these receiving circuits are utiin a southerly direction, the number of passagesk across the gaps C while traveling in a westerly` direction and the number of passages across the gaps C while traveling in an' easterly direction.

The difference between the numbers registered by the north and south counters gives the distance traveled north or south and the difference V between the numbers registered by the east and west counters gives the distance traveled east or west so that Ythe subdivision in which the craft is located may be determined. at any time. One of the counters is actuated upon each passage of the craft from one of'two parallel border beams to the other without crossing an intermediate beam and the selective actuation of the north and south counters and east and west counters is dependent upon the order in which the `circuits tuned to the border beam frequencies are energized.

A set of lamps G arranged in the pattern of` the subdivision vare controlled by the receiving circuits to successively light the lamps to indicate the position of the craft in the subdivision in which it is traveling.

A recording device H controlled by the lamp circuits gives a visible indication of the course of travel of the. craft and makes a permanent record thereof. The recording device H comprises a tape exposed through a window opening in the board E. The tape II is moved continuouslyv and uniformly by a suitable clock driven device or the like and. along an edge of the window opening. a row of styluses I3 are mounted. As shown in Fig. 5, each stylus is normally held in a nonengaging position by a spring I4 and is moved into engagement with the tape I I by means of a solenoid I5 in the circuit of vone of the lamps G. Each mark made by the stylus is a permanent record of the position of the craft at the time the niark was made and the succession of marks on the tape will enable tbe path of the craft to be plotted on a map as indicated at K in Fig. 1. The recording device in addition'to giving a visual indication of the path of travel serves to indicate anv receiving circuit that is defective and any sending station that is inoperative. It also provides means for` accurately determining position even though oneor more receiving circuits or one or more sending stations be out of order. v

In order to facilitate the reading of the recor on the tape II and detection of failures of receiving and signaling circuits. four marking devices |6- operated by solenoids I'I. onein each counter circuit as shown in Fig. 2 may be prothe circuits of the lamps G, each of which is controlled by the switches of two panels, one of each set. The lights are connected by wires La., Lb, Le and Ld to panels Ps, Pb, Pc and Pd and by wires L1, L2, L3 and L4 to panels P1, P2, P3 and P4. During operation the switches of the two panels, one of each set, last energized remain closed and complete the circuit through the lamp which indicates the two beams, one of each series, last crossed by the craft. The same circuits control the styluses to indicate on the tape l I the periods of time during which each lamp circuit has been closed.

The receiving circuits preferably include a band pass filter since it is desirable that the control devices be sensitive only to modulation frequen cies outside the audible range. A. suitable delay network may also beassociated with each receiving circuit so that waves of the selected frequency mustimpinge upon the receiving circuit for an appreciable length of time before energization of the control elements becomes effective.

The switches and switch actuators of the control panels are shown in Fig. 3 of the drawings which shows control panels P1, P2, and P4, panel P3 being omitted because it is identical with Pz. Each receiving circuit has a solenoid I3 mounted on its associated control panel and each solenoid controls the operation of the switches of its panel.

The control circuits are connected across lines 2lin and 2| and the panels Pa to Pb are identical with panels Pi to P4 except that the' connections from lines 2D and 2| to the panels of one set are reverse to those of the other set. The solenoid I 3 of eachrof the panels P1 and P4 operates a sliding switch member 22 that carries three contact members 23, '24 and 25. The solenoid it of the panel P2 operates a sliding switch member 22a that is identical with the members 22 except that it carries contact members 23 and 24 only. The contact member 23 serves to energize a relay controlling the circuit of one of the lamps G. The contact 24| serves to control a relay opening circuit and the contacts 2'5 control counter actuating circuits.

The sliding switch members 22 andV 22a are connected by wires 26 to theline 2| and are normally held by springs 2'I in open positions. The contact members 23 are movable into engagement with contact members 28 to close a circuit from the line 2| through the wire 26 contact members 23 and 28, a wire 29, a relay solenoid 30 and a wire 3| to the line 20. The solenoid 30 operates a normally open switch 32 that closes a circuit from line 2| through wire 26, a wire 33, the switch 32, a wire 34, a normally closed switch 35, a wire 36, the solenoid 30 and wire 3| to line 20. The

solenoid 3|] also operates a switch 31 that when vided to indicate on the tape each crossing from Y one subdivision to another and the direction'of such crossing. The receiving' circuits are arranged in two groups, one group being tuned to the frequencies a, b, c and d and designated Ra, Rb, Re and Rd and the other group being tuned to the frequencies I. 2, 3 and 4 and designated R1. Re, R3 and R4. Each receiver has a control panel associated therewith, `the panels of yone group being designated Pa, Pb, Pqan'dV Peandjthe other group being vdesignated as P;,' l?2, P,3,; ,and ,75

P4. The oo ntrol panels have switches controlling closed connects a lamp circuit wire L to the line 2|l through a wire 38 and wire 26.` In the series of panels Pa to Pd the switch members 22, 22a are connected to the line 20 instead of 2| so that each lamp circuit is completed through l two' switches 31, one on a panel 'of 'each series.

The relay circuits areso controlled that vno two relays of the same series can be closed 'at the same time, the main switch of each panel operating to open any previously closed relay. Therefore, at any given time all relays of each series except the one controlled by the radio circuit last energized will be open and one lamp circuit will be closed. l The closed circuit being that voi the lamp positioned to correspond to the intersection 'of the'two' beams last'c'rossed by the craft', the

course of the craft across each subdivision traversed being indicated bythe lamps G successively lit during the passage.

The `relay circuits are de-energized by opening the normally `closed `switches 35 and this' is accomplished byvmeans of solenoids 39 that are i movement of any one of the sliding switch members 22 or 22a before engagement of the contact Amember 23 with the contact member 28.

The contact members 45 are pivoted trip members thatmake contact only during the closing movement of the switch members. As shown in Fig. 4 the member 45 has a body portion `46 of insulating material 4and is 4pivotally mounted on a Xed supporting member 47. The member 445 is engaged by a leaf spring 48 that normally holds they member in upright position. The member 45 has a pointed top that is in the path of movement of the `contact member 24 and is provided with `a contact plate 49 on the side thereof toward which the contact member moves when the switch member is actuated by the solenoid I8. As the switch member moves towardcircuit clos ing position, the contact 24 engages the plate 49 and completes the circuit from the line 2| `through the wire 2li, contacts 24 and 45, wire 44, solenoidss39 and'rwires 4I, 40 and `3i to line 28, breaking all the relay circuits of the series. After thecontact `member 24 has `passed the contact member'45 the relay of the energized panel is closed by engagement of contacts 23` and 28. The relay'so energized stays energized until an'- oth'er `radio circuit Aof the series is energized by crossing another of the controlling beams. Upon the return movement of the contact member 24 after deenergization of the solenoid I8 it engages theside of the member 45 opposite that which carries the contact plate 49 so that no electrical contact is made.

As the lights G are lighted the corresponding styluses I3 are Vactuated to record the course of travel on the tape I I.

On each of the panels that are controlled by border beams such as the panels P1 and P4 in Fig. 3 the switch member 22 is provided with the additional contact member 25, that engages with a pivoted contact member 5I) that may be identical with the contact member 45, the member 50 being positioned closer to the contact member 25 so that the contact 25 engages the contact 5d before the contact 24 engagesithe contact 45.

The contact 50 of panel P1 is connected through va wire 5I, the east counter. a wire 52, the wire 33 oiy panel P4, the switch 32, the wire 34, the switch 35, the wire 36, the solenoid 3Ii`and the wire 3| to the line 420.` The contact 50 of panel 'P41' is connected through a wire 53 the West counter.` a wirev 54,` the wire 33 of panel P1, the switch 32, thewire 34, the V'switch 35, the wire 36,' the Vsolenoid 38 and the 'wire 3I to the line 20. If the relay of panel P4 is closed when the vcontrol switch of panel P1 is operated by the solenoid I8, the east counter is energized` If the relay of panel P1 is `closed when the switch of panel P4 is operated the west counter is energized. The counter circuits can be energized Yonlywhen the 'craft passes from one border beam to another of` the same series without crossing `intermediate beams. Referring to Fig. 1, it will' be seen ythat `this can happen; only when the `:craft passes :across one ofithegaps -C or D. Assuming that-one lof the gaps C is crossed bythe-craft traveling inA an'easterlydirection, it will be lapparent that thebeam 4 is rst crossed and then the beam .I. Crossing the beam `4 will close the relay on panel P4 and crossing the beam Ivwill complete the circuit for the east counter. In passing over the same gap `traveling west .the a beam will energize the relay of panel P1 and actuation ofthe switch on panel P4 will complete the `circuit for the West counter.

The nort and: south counters are connected in exactly the same way between panels Ps and Pd. The four markers IB in the circuits of the four counters as shown in Fig. 2 'will be Y actuated with the counters to indicate the direction of each crossing onrthe tape I I.

In the system as illustrated herein beamsof four frequencies are employed in each series. As shown in Fig. 3, three` frequencies 'in each series are all that are essential. Since all of the intermediate panels are identical, as manyv frequencies in excessy of three as desired may be employed in each of the two series. It is not lessential that `the same number of beams be provided in each series. If the number of beams in one series is greater than-those in the other, the subdivisions will be rectangularinstead of square, but the operation `will be the saine.` The beams of one series need not cross the'beamsof the other series at right angles, and the beams of one `vor both of `the :series lmay be divergent it being only necessary that the two series of beams be so related that their intersections will dene de'nite quadrilateral areas. It is to be understood that the` term.frequency as applied to the radio beams is intended ,to refer eitherto radio frequency' or modulation frequency. The

l'radio beams, may, if desired, all be of the same radio frequency but with'modulations of dif ferent frequencies, in which case a single radio receiver 54 having its output connected in parallel to the band pass filters 55`may be employed. as shown in Fig. 6 each one of the band pass filters 55 Vbeingv tuned to pass only one Vof the modulations.

In addition to operating the lamps and recording tape the control `mechanism may be utilized to `graphically indicate the geographical position of the Ycraft and the direction from the craft of any desired number of `stations with which it may be desired to establish radio communication or to which Vthelcraft may be traveling. Geographical position is indicated by` a member that has a movement with respect to a dial that corresponds to the movement ofthe craft with-respect to the earths surface. The direction indicating devices may be in the form of pointers controlled by the moving member `which indicate on the dial the direction of'selected stations so that the directional receiving or transmitting antennae of the craft may be properly positioned with respect l toa desired station.

As shownA in Figs-7 to:l0, the pointer. actuating'mechanism is'mountedupon `a dial plateil which may if desiredrbe `mounted to turn about a central pivot BI to permit the dial tobe oriented so that the pointers will point in the true direction. However, the `angular direction will be indicated on-the dialregardless of the actual position or" the dial with respect to the compass;l i

As shOWnin'Fig. `7 Itwo parallel `bars 62 and B3 `are mounted-on 'runners 64 and 65 that slide on tracks 66 on the dial plate 60 at right angles to the bars. Two parallel bars 61 and 68 at right angles to the bars 62 and 63 are mounted on runners '68 and 10 to slide on tracks 1| on the dial plate 60 at `right angles'to'the bars. Shafts 12 and 13 are mounted on rthe dial plate 60 at opposite sides thereof parallel to the bars 02 and 63. Cables 14 anchored at vone end to the dial plate 60 passover pulleys 15 on the bar 62 to drums 1B on the shaft 12. rCables 11 anchored at one end to the dial plate |50v pass over pulleys 18 on the bars 63 to drums 19 on the shaft 13. Shafts 80 and 8| are mounted parallel to the bars B1 and B8 at opposite sides of the dial plate. Cables 82 extend from drums 83 on the shaft 80 over pulleys 84 on the bar 61 to an anchor on the dial plate. Cables 85 extend from drums 8S on the shaft 8| over pulleys 81 on the bar 58 to an anchor on the dial plate. By means of the kshafts 12, 13, 80 and 8|, the bars 62, |53, 61 and 68 may each be independently moved. At the points where the bars 32 and 63 cross the bars 61 and 58, lslide blocks 88 are mounted, each block having two holes at right angles to receive the crossing bars. Two straight slotted bars 89 are pivoted, one to each of two blocks 88 that slide on one of the crossing bars, and are guided by studs 30 mounted in diagonally opposite blocks 88 'and engaging in the slots of the bars 89. At the crossing point of the two bars 89 two blocks 8| and 92 are slidably mounted on the bars 88 and are connected together by a central pivot 93 that passes through the slots of the bars 89 and ing bars 62, 63, 61 and 68. A disk 04 is supported beneath the block 92 by the pivot 93 and is held vagainst angular movement with respect to the dial plate 60 by means of links 06 pivoted to the bars 89 at equal distances from the pivoted ends thereof and connected together by a pivot 9T that slides in a slot 98 in an arm 99 attached to the disk' 94. Pointers |00 are connected at any desired points to the disk 94 by pivots |0| and each is guided by a swiveled eyelet |02 that may be mounted on a thumb tack |03 that may be secured at any desired point on the dial plate 60. The pointers are preferably provided with curved innerends |04 that will permit the swivel eyelet |0| to occupy a position directly beneath the pivot |0i. Each of the four shafts 12, 13, 80 and 8| is provided with a ratchet wheel |05 that may be operated step by step by a pawl |06 carried by a lever |01 that is actuated by a solenoid |08 and an opposed spring |09. Wires for energizing the solenoids |08 may be led to the bottom of the plate 60 through the pivotl 5| so as not to interfere with the orienting of the dial plate.

The solenoids |08 are in circuits controlled by the radio receiving'circuits, as shown in Fig. 11, so that the bars 62, 63, 61 and 68 are moved north, south, east and kwest a predetermined dis- 'of the craft with respect `to the earths surface.

' The solenoids |88 are 'in circuits selectively controlled in the same manner as the circuits of the counters F above described.' The counter circuits shown in Fig. 3 could be employed but it is preferable that a movable bar' of the indicating device be actuated each time the craft v crosses a space between any two successive parallel radio beams so that the disk 94 Will have movements corresponding to that of the craft across the individual subdivisions. This requires a slight alteration of the control circuits which is illustrated in Fig. 11. As shown in Fig. l1, a sliding switch member 22 having three contact elements is provided on the intermediate panels Pb and Pc as well as on the panels Pa and Pd. Each one of the solenoids |08 is energized by means of any one offour solenoids |08a, |031), |08c, and |08d that operate switches ||3 connected in parallel between one terminal of the solenoid |08'and the power line. North and south solenoids |03l are shown in Fig. ll and the solenoids |08a to |08@ associated with the two solenoids |08 are referred to as nort and south solenoids.

The contact 50 of the panel Pa is connected by a wire H4 to one terminal of the north solenoid |884; and to one terminal of the south solenoid |08a. The opposite terminal of the north solenoid |03a is connected by a wire 5 with the wire 33 of the relay on the panel Pd, and the opposite terminal of the south solenoid |08a is connected by a wire ||6 to the wire 33 of the relay of the panel Pb.

The Contact 50 of the panel Pb is connected by a wire ||1 to one terminal of the north solenoid |0815 and with one terminal of the south solenoid |0810. The opposite terminal of the north solenoid Hlth is connected by a wire ||8 to thewire 33 of the relay on the panel Pa and the opposite terminal of the south solenoid |081) is connected by a wire ||9 to the wire 33 of the relay'on the panel Pc.

'I'he contact 50 of the panel Pe is connected by a wire |28 with one terminal of each of the north and south solenoids |086. The'opposite ter-minalof the north solenoid |08c is connected by a wire 12| with the wire se on the panel Pb and the opposite terminal of the south solenoid |08c is connected by a wire |22 to the wire 33 of the panel Pa.

The contact 50 of the panel Pd is connected by a wire |23 to one terminal of each of the north and south solenoids |0811. The opposite terminal of the north solenoid |08d is connected by a wire |24 to the Wire 33 of the panel Pc and the opposite terminal of the south solenoid |08d is connected by a wire |25 to the wire 33 of the panel Pa.

The east and west solenoids |08 are controlled from panels P1, P2, P3 and P4 in exactly the same way as the north and south solenoids |08 are controlled from the panels Pa, Pb,

Pc and Pd.

Each time the craft crossesfo-ne of the controlling radio beams one or the other of the two circuitscontrolled by the contact 50 of the energized panel will beenergized unless the energization is caused by a second crossing of the same beam while the relay of thepanel controlled by that beam is still closed, in which case no circuit is completed throughl the contact 50. Whenever the craft crosses the beam a traveling north from the beam. d to the beam a, a circuit will be completed from line 20 through wire26, contact 50, wire IM, north solenoid |038,v wire 5 to wire 33 of the relay on panel Pd and through the relay to wire 3| and line 2| causing an actuation of the "nort solenoid IBB. `If thecraft crosses y tween successive beams and the directionA thereof. The face of the dial plate 5i) may be sectioned by lines parallel to bars G2, 63, 6l' and 68 and spaced apart a distance equal to the movement of .the `disk 94 upon each actuation of a ratchet H35.

The pointing mechanism may' be set at any desired. time or place for example before leaving the home station. Assuming a pointer center to be the position of the craft at the time the. setting is` made, it will be apparent that the point on.. the dial plate corresponding to the position of any station within the. area covered by the beams may be readily located. The pointer guiding eyelet will be positioned at such point and since the movements of the disk 94 with respect to the dial plate B correspond to the movements of` 'the craft with respect to fixed points en the earths surface, Vthe pointer will continue. to point tothe station for which it is set. If .the station to which ther pointer is directed is the destination of the craft, the eyelet guide will be directly below the pointer pivotand the pointer will swing freely when the craft arrives at its destination. Also if the eyelet m2' is set with its swivel in axial alinement with the pivot lill at the home station, the pointer will be directed to the home station until the device is reset.

The movement of vthe disk 94 with respect to the dial Ell upon each actuation corresponds to the movement of the craft through a space between successive radio beams and the travel `of the. disk 94 .across ythe dial plate corresponds to the travelof the craft over the earthssurface. It will be apparent therefore that if a map drawn to the proper scale of the region in which the craft is traveling be xed to the plate 6l), a pointer held in fixed position with respect tothe disk 94 may be positioned` to indicate the rposition y of the. craft on the inap.

VThe pointing device will enable the operators of the traveling craft to quickly orient their radio apparatus with respect to desired stations other than. those to which the pointers are directed.` f

' The north counter F may be connected in rthe line I I5, the south counter in the line and the east and west counters may be correspondingly placed in the circuits controlled by panels P1 t0 P4.

If it be desired to keep eachlight that is lit. on the, panel G lighted until another subdivision is entered in order to provide a visual indication of the direction and course of travel of the craft across. each subdivision, this may be accomplished bythe modification'of the light and stylus conv |Il8d to register each passage across the space betrolling.circuits-.shown in.` Fig. 12. Referring to Fig.`-12; eaclrfothe.` sixteen. stylus actuating solenoids I5, two` of which are shown, has its terminals connected to-one of. the wires La to Ld and to one of` the vwiresLi to L4, asin the modification previously described. The. lights, however, are in relay circuits controlled by the solenoids I5; Each stylus .IBcarries a brush contact |26 that engages a stationary Contact,` |21 and completes a circuit from. line 20 through aline |28, wire |29, a relay solenoid |30, a'wire |3|,.the contacts |26 and |21 and wires i|32 .and |33 to. lineh 2|. Energization ofthe solenoid` |30 closes .a relay switch |35 and closes-.a circuitfrom'line 20 through wires |28, I29,-solenoid |50, a. light. G, the switch |35, and Wire |33 to line 2l. v'Ihe stylus operating solenoids each will remain energized. until one of the two panel relay. switches in series with it is opened. The associatedlamp however will remain lit until its relay circuit isbroken. The lamp relay circuits may be controlled by four normally closed switches |31 inA the. line |2B,.each adapted to be opened by a solenoid |38 connected in one of the counter circuits .to be energized upon passage of the craft `from onesubdivision to anotherl As shown in Fig. 12, one of the solenoids |38. is in the line I|5-that connects the north counter to the panel Pd and another is connectedin the line |25 that. connects the. south counter to the panel Pa. The other two solenoids |37 are connected infthe corresponding counter circuits controlled by the panels VPi to P4.` One of the solenoids |38 will` be energized upon. eachl passage of the craft from one subdivisionto another to open all of the light relay circuits.

If a Visual indication ofthe course of travel over a distance greater Vthan .the distance-across asubdivision is desired, a suitable. stylus attached to the disk 94 will trace the course upon a map secured against the face of-the dial plate 6D.

If a more exact indication of position is desired one or more additional systems of crossing beams may be employed which have their'beams interposedbetwee'nfthe beams ofthe first series as is indicated on the subdivision marked B2V in Fig. 1 and additional control panel sets may be'provided on the craft to register travel with` respect to the beams of the additional systems. The sets of lights controlled by all ofthe control panel sets maybe placedupon asingle panel positioned as indicated by the intersections between the crossingbeams of .each system on the subdivisionV B2 in Fig.. 1.

By means of the control `circuits herein described thev radio receiving circuits may be made to control four. separate and distinct position indicating devices, namely vthe counters, the bank of lights, the recording device and the graphic indicator. It `will be` apparent that any one of the indicating devices may be employed. alone or that two or more of the indicating devices Vmay be combined.

If desired' four counters may be employed that will each register all crossings in a given direction across spaces between parallel beams. Such movements 0f the craft are registered on the graphic indicating device by means of. the control circuits shown inl Fig.A l1. If it be desired to register these movements by means of counters rather than byineans of the disk 94, each of the vsolenoids |08 may actuate a counter.

If ve. or more radiofrequencies belemployed in' each series the travel indicating elements may beso controlled as to automatically compensate for the failure of any individual receiving-circuit,

If seven radio frequencies be employed the failure of any single circuit or any two circuits that are normally energized successively may be compensated for. Such compensation is particularly desirable for maintaining the accuracy of the graphic indicator which would normally be adversely aiected by the failure of any radio receiving circuit due to a defect in the circuit or failure of a beam transmitter. The compensation for skipping single beams may be obtained by registering any passage in either direction across the space between alternate beams without energization of the receiving circuit tuned to the intermediate beam and imparting to the indicator twice the movement that would normally have been imparted thereto upon energization of a radio receiving circuit.

Similar compensation may be provided for the skipping of two or more successive beams.

In Figs. 13 to 15 of the drawings lav control system for the graphic indicator is shown in which seven control panels Pa-Pg are employed for registering north and south movements, it being understood that identical means may be employed for registering east and west movements. As shown in Fig. 13 the shafts 12 and 13 are each provided with two ratchets |50 and in addition to the ratchet |05. The solenoids |08 operating the ratchets |05 are controlled by switches on panels |52 and |53 that are operated by solenoids |08a--I08g on'each panel controlled by the contacts 50 of the panels Pa to Pg in the manner illustrated in Fig. 14. The north solenoid |08 is energized upon the closing of any one of the seven solenoid operated switches ||3 on the panel 52 and the south solenoid |08 is energized upon the closing 'of any one of the seven switches on the panel |53, the solenoids |08a|08g of panels |52 and |53 being connected to the panels Pg and Pg in the manner shown in Fig. 11. The ratchet |50 on the shaft 12 is operated by a solenoid |54 controlled by switches on a panel |55 and the ratchet |50 on the shaft 13 is operated by a solenoid |56 controlled by switches on a panel |51. The ratchet |5| on the shaft 12 is operated by a solenoid |58 controlled by switches on a panel |59 and the ratchet |5| on the shaft 13 is operated by a solenoid |60 controlled by switches on a panel 16|.

The contact 50 of each of the seven control panels Pa-Pg is connected by a wire |62 to one terminal of one of the solenoids |08a-'|08g of each of the panels |52 and |53 and the relay wire g3 of each of the panel Pe-Pg is connected by a wire |63 to the opposite terminal of one of the solenoids |06a-I06g of each ofthe panelsl |52 and |53. The contact 50 of panel Pg is connected through one of the wires |62, with solenoid |083 of panel |52 and one of the wires |63 to the relay Wire 33 of panel Pg and through a wire |62, south solenoid |088 of panel |53 and a wire |63 to the relay wire 33 of panel Pb. The contacts 50 of the other control panels are each similarly connected through a solenoid on each of the switch panels |52 and |53 so that travel across each space between successive beams in a north or south direction is registered by actuation of one of the solenoids |08. In normal operation the'shafts 12 and 13 are actuated by the solenoids |06 only.

The switch panels |52 and |53 are identical, each having seven solenoid operated switches connected in parallel between wires |64 and |65 connecting one terminal of the solenoids |08 with the'power line as shown in Fig, 14 so that closing of any one of the switches on the panel |52 Will energize the north solenoid |08 and closing any one of the switches on the panel |53 will energize the south solenoid |08. The solenoids |08a|08g of the panel |52 are connected between contacts 50 of the individual control panels and relay wires 33 of panels controlled by the next beam to the south of that causing energization of the contact 50 in the manner shownv in Fig. 11.

The switch panels |55, |51, |59 and |6| are each identical with the switch panels |52 and |53. solenoids |54 and |58 are connected in parallel with north solenoid |08 between lines |64 and |66 and solenoids |56 and |60 are similarly connected in parallel with south solenoid |08.

The contact 50 of each control panelY is connected through wires |62, and |63, and one of the switch operating solenoids of the panel |55 to the relay wire 33 of the panel that is energized by the beam located two spaces to the south of the beam that causes actuation of the contact member 50, and through wires |62 and |63 and one of the switch operating solenoids of the panel |51 to the relay wire 33 of the panel that is energized by the beam located two spaces to the north of the beam that causes actuation of the contact member 50.

The contact member 50 of each control panel is connected through wires |62 and |63 and one of the switch operating solenoids of the panel |59 to the relay wire 33 of the control panel that is energized by the beam three spaces to the south of the beam that causes actuation of the contact 50, and through a switch operating solenoid on the panel |6| to the relay wire 33 of the panel that is energized by the beam three spaces to the north of the beam that causes actuation of the contact 50.

The solenoids `|54 and |56 are energized only when one of the beams has been crossed without energizing the circuit tuned to the frequency of that beam. The solenoid |53 and |60 are energized only when two successive beams have been crossed without energizing Ieither of the circuits on the craft tuned to the frequency of those beams.

The ratchets |50 and |5| are so operated that each ratchet |50 imparts upon each actuation, a movement to its shaft that is twice that imparted by an actuation of the associated ratchet |05 and each ratchet |5| imparts to its shaft upon each actuation, a movement three times that imparted by an actuation of the associated ratchet |05. For example the solenoid |03 may move the ratchet |05 one tooth space, the sole noids |54 and |56 may each move its ratchet 2 tooth spaces and the solenoids |56 and |60 may each move its ratchet three tooth spaces.

The contact 5|) of the panel Pa is connected through the switch panel |52 to the relay of the panel Pg, through the switch panel |53 to the re'- lay of the panel Pb, through the switch panel 55 to the relay of the panel Pf, through the switch panel |51 to the relay of the panel Pc, through the switch panel |59 to the relay of the panel Pe, and through the switch panel |6| to the relay of the panel Pd. The contact 56 of the panel Ps is thus provided with a separate connection to the relay of each of the other panels, each causing energization of a different solenoid. Each of the other contacts 50 is similarly connected. Fig. 13 shows a. control system in which all of the possible rection opposite that of actual travel.

connections are utilized. It will be apparent, however, that removal of the switch panels |59 and |6| and the ratchets' |5| would not in any way affect the operation of the ratchets |95 and |50, and that, if all the switch panels except |52 and |53 were removed the system would be the same as that illustrated in Fig. 11, In the seven frequency system illustrated, the skipping of a single beam or of two successive beams may be compensated for by utilizing all of the possible connections from the contact Eil of each panel to the relays of the other panels. By utilizing a -greater number of frequencies the number of skips that can be compensated for may be increased. If 21H-1 frequencies are employed any skips up to and including n-l successive skips may be'compensated for It is not necessary that the number of frequencies'be an odd number since it is not necessary that the contact 56 of each panel be connected to the relays of all other panels. In the seven frequency system illustrated the skipping of three, four or five successive beams while traveling north would result in an actuation of one of the south solenoids lwhich would give a movement to the indicator in a di- It is apparent therefore, that likelihood of error may be reduced by increasing the numb-er of frequencies employed. When 2.?2-1-1 frequencies are employed there may be failure of as many as 211-2 control units, provided no more than n-1 successive beams are skipped.

The automatic compensating system illustrated in Fig. 13 facilitates the coverage of a large area by beams from a single row of transmitting stations. Powerful beams `may be alternated with relatively weak beams so that the weaker beams will be skipped in portions of the control area remote from the sending stations.

It is to -be understood that variations and modications of the specific device herein shown and described for purposes of illustration, may be made without departing from the spirit of the invention.

What I claim is:

1. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series diering in frequency and the beams of one series intersecting the beams of the other to provide a checkerwork area over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, and means controlled by sequential energizations of said circuits for indicating the intersection of the two beams, one of each series, last crossed by said craft.

2. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, whereby the checkerwork area is divided into subdivisions by groups of beam intersections, a series of radio receiving circuits on a craft traveling in said 'checkerwork area which are tuned, one to each of the beam frequencies, means controlled'jointly b-y radioA receiving circuits tunedto' the frequencies ofv the beams of one series and receiving circuits tuned to the frequencies of the beams of the other seriesfor indicating the intersection of the two beams, one of each series, last crossed by the craft in the subdivision in which the craft is traveling, andmeans controlled by said receiving circuits for indicating passage from one subdivision to another.

3. lA position indicating system for craft traveling over a portion of the earths surface which comprises |means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, elements suc-cessively operated by said receiving circuits as they are energized, and means controlled by said elements for indicating the direction and path of travel of the craft.

4. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a icheckerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number offrequencies which recur in regular sequence, whereby the checkerwork area is divided into subdivisions by groups of beam intersections, a series of radio receiving circuits on a craft traveling in said checkerworkarea which are tuned, one to each of the beam frequencies, elements successively operated by said receiving circuits as they are energized, means controlled by said elements for indicating the direction and path of travel of the craft, and means controlled by said elements for registering passages from one subdivision to another.

5. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, elements successively operated by said receiving circuits as they are energized, a series of signaling circuits, control switches in said circuits, and means controlled by said receiving circuits for operating said switches.

6. A position indicating system for craft travcling over a portion 'of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion'of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, whereby the checkerwork area is divided into subdivisions bygroups of beam intersections, a series of `radio receiving circuits on a craft traveling in said,checkerwo`rk area which are tuned, one to each of the beam frequencies, elements successively operated by said receiving circuits as they are energized, a series of electric circuits, means controlled by certain of said circuits for indicating the path of travel of the craft across each subdivision, means controlled by other of said circuits for registering passages of the craft from subdivision to subdivision in each direction transversely of the beams of either series, and switches in said electric circuits controlled by said receiving circuits.

'7. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, whereby the checkerwork area is divided into subdivisions by groups of beam intersections, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, elements successively operated by said receiving circuits as they are energized, a lamp panel having lamps thereon arranged to correspond to the beam intersections of a subdivision, circuits for said lamps, and switches in said lamp circuits controlled by said receiving circuits. l

8. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of fre-l radio beams with the lbeams of the two series differing in frequency and intersecting to providea checkerwork of intersecting beams over said portionof the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, Whereby the checkerwork area is divided into subdivisions by groups of beam intersections, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, land devices for indicating passage from -one subdivision to another, each controlled by a pair of receiving circuits tuned to the frequencies of beams of the same series forming opposite borders of a subdivision. Y

10. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, devices for indieating passage from one beam to another, each controlled by a pair of receiving circuits tuned to the frequencies of said beams, another pair of circuits controlled by each of the first mentioned pairs, and means controlled by the last mentioned pairs of circuits for indicating distance traveled in each of four directions.

11. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a' predetermined number of frequencies which recur in regular sequence, whereby the checkerwork area is divided into subdivisionsv by groups of beam intersections, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, means for indicating the path of travel of the craft across each subdivision comprising signals, each controlled by two of said receiving circuits, one tuned to a beam of one series and the other tuned-to a beam of the other series, and devices for indicat ing passage from one subdivision to another, each controlled by a pair of receiving circuits tuned to the frequencies of beams of the same series forming opposite borders of a subdivision.

12.V A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, whereby the checkerwork area is divided into subdivisions by groups of beam intersections, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one

to each of the beam frequencies, means for indi- Y eating the path of travel of the craft across each subdivision comprising signals, each controlled by two of said receiving circuits, one tuned to a beam of one series and the other tuned to a` beam of the other series, devices for indicating passage from one subdivision to another, each controlled by a pair of receiving circuits tuned to the frequencies of beams of the same series forming opposite borders of a subdivision, and means controlled by said pairs of receiving circuits for indicating distance traveled in each of four directions.

13. A position indicating system for craft traveling over a portion of the earths surface which comprises .means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, separately energized circuits controlled by said receiving circuits, and means operated by said separately e`n ergized circuits for recording the course traveled by said craft.

14. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, separately energized circuits controlled by said receiving circuits, position indicating signals operated by said separately energized circuits, and means operated by the latter circuits Vfor recording the course traveled by said craft.

15. A position indicating device comprising a series of differently tuned radio receiving circuits, separately energized circuits, each controlled by a pair of said receiving circuits, and signals controlled by each of said separately energized circuits.

16. Aposition indicating device comprising differently tuned radio receiving circuits arranged in'two series, a signal panel having a number of rows of lamps corresponding to the number of receiving circuits of one series and a number of lamps in each row corresponding to the number of receiving circuits of the other series, a circuit for each of said lamps, and two switches in each circuit, means controlled by a receiving circuit of one series for operating one of said two switches in each lamp circuit and by a receiving circuit of the other series for operating the second of said two switches.

17. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, and two pairs of radio receiving circuits on a traveling craft, the circuits of one pair being tuned to the frequencies of two successive beams of one series and the circuits of the other pair being tuned to the frequencies of two successive beams of the other series, and means selectively controlled by each pair of receiving circuits for indicating sequential energizations of the circuits and the order of the energizations.

18, A position indicating device comprising two pairs of selectively tuned radio receiving circuits, a pair of counters associated with each pair of receiving circuits, and means for counting energizations of each circuit of each pair that follow the energization of the vother circuit of the pair to measure travel in four directions.

19. A position indicating system for craft traveling over a portion of the earths surface which, comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, and two pairs of radio receiving circuits on a craft traveling in said checkerwork area, the circuits of one pair being tuned to the frequencies of two successive beams of one series and the circuits of the other pair being tuned to the frequencies of two successive beams of the other series, a pair of counters associated with each of said pairs of circuits, and means controlled by eachpair of receiving circuits for operating one of the pair of associated counters upon an energization of one of the receiving circuits that follows an energization of the other receivingcircuit of the pair and for operating the other counter of the pair upon energization of the same circuits in the reverse order.

20. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to Vprovide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, in combination with radio receiving circuits on a traveling craft tuned to thev frequencies of said beams, a dial, four elements, each movable in a different direction over said dial, means controlled by said receiving circuits .for imparting movements to each of said elements proportional to `movements of the craft in a corresponding direction with respect to the earths surface and means controlled by said movable elements for imparting movements to an indicating element corresponding to movements of the craft with respect to the earths surface.

21. The herein described method of indicating the position for craft traveling over a portion of the earths surface wlnch comprises forming a checkerwork of intersecting radio beams over a portion of the earths surface, said checkerwork being formed by two series of beams, the beams of each series having a predetermined number of frequencies which recur in regular sequence, said frequencies providing a number of combinations at beam intersections equal to the number of frequencies in one series times the number of frequencies in the other series, said combinations dividing the checkerwork area into subdivisions, energizing a tuned radio receiving circuit on the craft upon each passage of the craft across a beam, operating a signal that indicates the intersection of the two beams, one of each series, last crossed by the craft, maintaining the signals so operated to indicate successive positions of the craft and its path of travel, and clearing the signals upon passage of the craft from one subdivision to another.

22. The herein described method of indicating the position for craft traveling over a portion of the earths surface which comprises forming a checkerwork of intersecting radio beams over 'a portion of the earths surface, said checkerwork being formed by two series of beams, the beams of each series having a predetermined number of frequencies which recur in regular sequence, said frequencies providing a number of combinations at beam intersections equal to the number of frequencies in one series times the number of frequencies in the other series, said combinations dividing the checkerwork area into subdivisions,

of the other series to determine distance traveled in each of four directions.

23. Avposition indicating system for craft traveling over a portion ofthe earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a Acheckerwork of intersecting beams over said portion. of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequence, whereby the checkerwork area is divided into subdivisions by groups of beam intersections', a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, `one to each of Vethe beam frequencies, separately energized lamp signal circuits controlled, each by two radio receiving circuits tuned one to the frequency of a beam of one series and the other to the frequency of a beam `of the other series, means for maintaining each lamp circuit after energization, and means controlled by certain of said receiving circuits for deenergizing all lamp circuits.

24. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each series having a predetermined number of frequencies which recur in regular sequencel whereby the checkerwork area is divided into subdivisions by groups of beam intersections, a series of radio receiving circuitsv on a craft traveling in said checkerwork area which are tuned, one to each f ofthe beam frequencies, means controlled by saidVV 25. A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beams of the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of eachl seri-es having a predetermined number of frequencies which recur in regular sequence, a series of `radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, means controlled by said receiving circuits, for indicating each passage across a space between successive beams and the direction traveled, and additional means for indicating passages between alternate beams upon failure of the circuit tuned to the intermediate beam.

26. .A position indicating system for craft traveling over a portion of the earths surface which comprises means for transmitting two series of radio beams with the beamsof the two series differing in frequency and intersecting to provide a checkerwork of intersecting beams over said portion of the earths surface, the beams of each sel ries having a predetermined number of frequencies which recur in regular sequence, a series of radio receiving circuits on a craft traveling in said checkerwork area which are tuned, one to each of the beam frequencies, movable indicating elements for indicating travel in four directions, means controlled by the receiving circuits tuned to adjacent beams for actuating said elements upon passage of the craft across a space between successive beams, and means controlled by receiving circuits tuned to non-adjacent beams for Vlivrait-articg proportionally increased in05u21meritstoV Y Y 

